VLF WAVE LOCALIZATION IN THE LOW-ALTITUDE AURORAL REGION

Localized packets of electrostatic whistler emissions near the lower h ybrid frequency have been observed in the low-attitude auroral region by sounding rockets and the Freja satellite. We present a model for wa ve localization that requires two ion species, O+ and H+, whereby the minority H+ ions control the localization process. The theoretical bas is is that the plasma dispersion is dramatically affected by small cha nges in the H+ density and that the observed emissions would selective ly heat H+. We show observational support for the proposed model.